An Optimization for the Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)
RFC 7466

Received changes through RFC Editor sync (changed abstract to 'The link quality mechanism of the Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP) enables "ignoring" some 1-hop neighbors if the measured link quality from that 1-hop neighbor is below an acceptable threshold while still retaining the corresponding link information as acquired from the HELLO message exchange. This allows immediate reinstatement of the 1-hop neighbor if the link quality later improves sufficiently.

NHDP also collects information about symmetric 2-hop neighbors. However, it specifies that if a link from a symmetric 1-hop neighbor ceases being symmetric, including while "ignored" (as described above), then corresponding symmetric 2-hop neighbors are removed. This may lead to symmetric 2-hop neighborhood information being permanently removed (until further HELLO messages are received) if the link quality of a symmetric 1-hop neighbor drops below the acceptable threshold, even if only for a moment.

This specification updates RFC 6130 "Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)" and RFC 7181 "The Optimized Link State Routing Protocol Version 2 (OLSRv2)" to permit, as an option, retaining, but ignoring, symmetric 2-hop information when the link quality from the corresponding 1-hop neighbor drops below the acceptable threshold. This allows immediate reinstatement of the symmetric 2-hop neighbor if the link quality later improves sufficiently, thus making the symmetric 2-hop neighborhood more "robust".')